In the early 1930s, work started on twin-row configurations of the three radial piston engines in production.

By Pratt & Whitney's tenth anniversary, it was making engines that were making history.

The Twin Wasp was the first twin-row design. Displacing 1,830 cubic inches, it delivered up to 1,350 horsepower and featured a new multilayered master rod bearing to withstand stresses at higher ratings. It performed magnificently and was selected to power fighters, bombers and transports. Partly due to the urgency of World War II, 173,618 engines were produced.